1. Field of the Invention
This invention relates to lactone esters of phenoxyisobutyric acid having valuable pharmaceutical properties, to a process for preparing the esters, to pharmaceutical preparations thereof, and to a method for their use. mole, 3
2. Prior Art
The association of excessive plasma concentrations of lipoproteins or of plasma lipids with increased risk of heart attack, stroke, and sudden deaths is well established. Consequently, the consensus of informed opinion is that elevated levels of cholesterol and/or triglycerides should be reduced by appropriate long term therapy.
The generally accepted Frederickson-Levy-Lees classification of lipid disorders based on lipoprotein disturbances lists five catagories, Types I to V, of hyperlipoproteinemia. This classification allows a more rational choice of therapeutic programs for the treatment of hyperlipoproteinemia, see R. I. Levy, Fed. Proc., 30, 829 (1971). Although a variety of drugs are available for the treatment of hyperlipoproteinemia, none of them is adequate for the general treatment of all types of hyperlipoproteinemias. At the present time, the preferred drugs for treating hyperlipoproteinemia are dependent on the classification of the syndrome and are thus specific for each syndrome; for example, see R. S. Lees and D. E. Wilson, New Engl. J. Med., 284, 186 (1971).
The esters of this invention have been found to be effective for reducing levels of cholesterol and triglycerides in the blood of mammals exhibiting hyperlipoproteinemia and associated conditions. The esters are effective at dosages which do not elicit undesirable side effects. Furthermore, the esters are effective for treating hyperlipoproteinemia in general, notably the syndromes comprising hyperlipoproteinemias of Types IIa, IIb, III and IV.
The lactone esters of this invention are prepared by a convenient process from readily available starting materials. Consequently, the esters are inexpensive and readily available.
The esters of this invention feature a combination of chemical subunits; namely, a lactone ester, comprising a 3-oxo-furan-1-yl moiety, associated with a phenoxyisobutyric acid. Esters of phenoxyisobutyric acid are known; for example, lower alkyl esters thereof are described in U.S. Pat. No. 3,262,850, issued July 26, 1966 and 3-pyridylmethyl esters thereof are described in U.S. Pat. No. 3,369,025, issued Feb. 13, 1968. Prior Art compounds are distinguished from the compounds of the present invention in that they lack the novel ester moiety of the compounds of this invention.